Using allelochemicals produced by submerged plants to inhibit algal growth is an environmentally friendly approach controlling harmful blooms in eutrophic lakes. This study aimed evaluate the inhibition of cyanobacterial accumulated aquatic plant Vallisneria natans, with enhancement through blue and red light-emitting diode (LED) supplementation. We conducted a laboratory experiment assess fluorescence parameters, enzyme activities, phycocyanin contents cyanobacteria Microcystis aeruginosa...

Information on orthophosphate (PO4-P) distributions in large oligo- and mesotrophic lakes is limited because PO4-P concentrations are low. Using a new procedure based ion chromatography, we determined spatio-temporal of biogeochemical parameters the north basin Lake Biwa 2018–2019 to clarify effects horizontal transportation nutrients phytoplankton growth. Above 20 m depth, chlorophyll peaked June–July October–November for 2018 2019 while usually remained < 0.03 μmol L−1. Distinct subsurface...

Black-odorous urban water bodies and sediments pose a serious environmental problem. In this study, we conducted microcosm batch experiments to investigate the effect of remediation reagents (magnesium hydroxide calcium nitrate) on native bacterial communities their ecological functions in black-odorous sediment water. The dominant phyla (Proteobacteria, Actinobacteria, Chloroflexi, Planctomycetes) classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Anaerolineae,...

The occurrence and distribution of microcystins were investigated in Lake Taihu, the third largest lake China. An extensive survey, larger broader scale than previous studies, was conducted summer 2010. highest microcystin concentration found at southern part which newly included this survey. In northern coastal areas, total cellular concentrations 20 to 44 μg/L observed. offshore waters, levels up 4.8 μg/L. Microcystin highly correlated with chemical oxygen demand, turbidity, chlorophyll‐a....

Effects of substrate and water depth on the physiological status a submerged macrophyte, Vallisneria natans (Lour.) H. Hara, were determined by measuring biomarkers in leaves roots, to understand factors limiting re-establishment V. urban eutrophic ponds. Ramets grown laboratory using aquaria containing bottom mud from pond maintained under sufficient light an incubator. The growth chlorophyll-a (Chl-a) content greater with than those sand, which was used as reference substrate. contents...

The river-lake transitional zone provides a unique environment for the biological community and can reduce pollution inputs in lake ecosystems from their catchments. To explore environmental conditions with high purification potential Lake Taihu indicator species, we examined river-to-lake changes water sediment quality benthic invertebrate communities of four regions. spatial variations observed this study followed previously reported patterns Taihu; northern western regions were...

The bivalve Anodonta woodiana is widely distributed throughout Chinese freshwaters and an important economic pearl mollusk.Recently, A. as a biomanipulation tool in lakes due to its strong suppression of phytoplankton, has been attracted increasingly more attention.In order examine whether can exert grazing pressure on Microcystis evaluate the different effects each algae diet mussels' potential growth, comparative study was carried out acute physiological responses variable microalgae diets...

Surface aerators have often been introduced in urban ponds for esthetics, but their roles remediating water quality are less understood. Effects of surface on controlling eutrophication were examined two ponds, which anaerobic odors and cyanobacterial blooms had occurred several installed. In one the a dramatic improvement dissolved oxygen (DO) (from 1.8 to 8.1 mg L−1) total phosphorus (TP) 1.6 0.4 was evident based comparison before after aeration. Although cyano-bloom did not occur,...

To understand the potential roles of terrestrial bamboo on controlling cyanobacterial blooms in aquatic systems, growth rates cyanobacterium Microcystis aeruginosa and its competitor algae were examined under different concentrations extract. In mono-species cultures with unicellular algal strains, 5.0 g L-1 extract treatment suppressed M. growth, while it had little effect green alga Scenedesmus obliquus or promoted diatom Nitzschia palea. co-species cultures, increased S. N. palea...

本研究は，湖沼において重金属 Cu2+ 汚染によるセキショウモ (Vallisneria asiatica) の抗酸化的生理情報を得るため，Cu2+ 濃度 0, 5, 10, 20, 40, 80 mg・L-1 の 6 処理区を設け，処理 12 日目に根と葉のクロロフィル，タンパク質とマロンジアルデヒド (MDA) の含量及びスーパーオキシドジスムターゼ (SOD)，カタラーゼ (CAT) とペルオキシダーゼ (POD) 活性を測定した．実験処理前に比べ，0 区では，根と葉ともにクロロフィルとタンパク質含量の減少，MDA 含量の増加，SOD と POD 活性の上昇が大きかった．5 区では，0 区より根と葉ともクロロフィルとタンパク質含量の増加，MDA 含量の減少，SOD 活性の上昇も少なかった．しかし，10 区では，根と葉のクロロフィルとタンパク質含量の減少，MDA 含量の増加，根の SOD 及び葉の CAT 活性の上昇が 5mg・L-1 区よりも大きかった．さらに 区では，10 区以上に根と葉とも Cu2+濃度の高くなる区ほど，クロロフィルとタンパク質の減少，MDA...

Field observations were conducted with respect to the vertical migration of dinoflagellate Peridinium bipes and its influence on nutrient transport in a stratified reservoir. P. migrated vertically circadian rhythms; that is, downward accumulated top layer hypolimnion from evening night then upward epilimnion early morning. In hypolimnion, rapid decrease concentration was observed evening, presumably due uptake by bipes. Active also suggested estimation descent velocity bipes, which...

The release of nutrients and metals from the sediment to overlying water induced by oxygen depletion is an important issue in eutrophic aquatic systems. Effects light-emitting diode (LED) illumination on conditions were examined comparing with those effects aeration microcosms using Lake Taihu, China. Periphyton filamentous algae developed surface LED (blue wavelength) treatment. Dissolved became rapidly saturated gradually supersaturated treatments, respectively, but remained low control. A...

Remediation of water quality by stimulating algal photosynthesis using light-emitting diodes (LEDs) has attracted attention, but few studies have examined this in outdoor freshwater environments. To understand the effects LED illumination on quality, dissolved oxygen (DO), temperature, pH, and electric conductivity were monitored over 5 months three depressions with or without a red/blue light at bottom an experimental pond. The blue evident period less rainfall after change to equilibrium...

The population density of the dinoflagellates Peridinium spp., mostly P. penardiforme, was surveyed from May, 1978 to March, 1981 at two sites in Ishitegawa Dam Reservoir : near dam site and head lake inflow Ishite River. increased 103-104 cells·ml-1 only winter, resulting a red tide. This abundant winter growth partly attributed low water temperature because our findings that grew more abundantly 10°C than 20° or 30°C cultures using filtered water. It also found phosphorus growth-limiting...

A boat equipped with UV lamps was developed to suppress freshwater red tide of the dinolagellate Peridinium bipes. The had two pipes at center bottom 20 installed inside each pipe. surface lake water directed into and expelled. radiations for over seconds were enough kill 100% cells when concentration less than 5.0×103 cells⋅ml-1 while 50 required ki11 90% more 1.0×104 cells⋅ml-1. Optimal velocity in regulated automatically between 17 35 cm sec-1 depending upon cell density ranging 2.0×103...

In the Seto Inland Sea in Japan harmful red tides have broken out year after causing a lot of coastal environment problems such as degradation scenery and damage to fish farming. To develop plankton control ship equipped with UV irradiation system, laboratory field experiments were undertaken investigate effects treatment on tide algae. clarify relationship between dose at 254 nm inhibition algal growth, several doses examined by adjusting distance samples lamp under different exposure...